I have a client requirement to monitor a region (say MyHome). To alert the user when he leaves MyHome and reaches back to the location. I can handle it pretty easily using the region crossing delegate methods:
locationManager:didEnterRegion:
locationManager:didExitRegion:
My question is, what will be the scenario if my device is off when I am at MyHome location. I leave the location MyHome, move to a different place and switch on my mobile. Will I get the locationManager:didExitRegion: delegate method fired when I launch the app back and thus will be able to notify that I am away from the region. OR will I have to do anything else to get this possible?
First of all monitoring region is not made for such small area to monitor. You may not get actual results. Now, the answer of your question, yes. It is possible. When you will start your device, you will have delegates method to get hit.
Related
I'm writing an app which use the location for two purposes:
1) It shows the user's location on a map (with navigation-like accuracy) in a location manager instance and delegate, contained in a viewcontroller
2) In the background, even when closed, it gets the nearest 20 points of interest (list stored in userdefaults) and activates a geofence for these, so the user is noticed when getting nearby. This is done by lowest accuracy possible (3km) to save power, and set up in another location manager instance, initiated when the app is first opened.
The problem is, that the CLLocationmanager object seems to be static so when I call it from two different places, it's the same instance that's returned, and the accuracy, intervals etc, seems to be the same, since both delegates are called simultaneously all the time.
Therefore, the geofences setup method is called all the time, when the user just move a little bit, which I want the map to reflect.
Yes, there's only one location manager. So reconfigure it when you go into the background and when you come back into the foreground. It may be convenient to switch its delegate to another object at those times as well (so that each delegate object can focus on one problem).
the CLLocationmanager object seems to be static
Yup! CLLocationmanager object is a Singleton so different objects cannot be created. To Solve your problem you need check you application status, which can be done using :
[[UIApplication sharedApplication] applicationState] == UIApplicationStateBackground
Once you know the application state you can configure CLLocationmanager's object properties accordingly. Hope it helps!
So I asked a question about my code relating to didEnterRegion but perhaps I was being too specific, therefore could I ask someone to clarify the order of method calls in more generic terms for region monitoring, specifically when the app is in the background.
My understanding is:
App registers region calling startMonitoringForRegion:
User taps home button or locks device, app goes into the background.
The devices location is monitored at the OS level, separate from the app, the app is never launched by the OS to confirm the users current location.
When the user crosses the boundary into the region, the OS looks for which app originally registered the region and launches that app.
The app is launched in the background, (didFinishLaunchingWithOptions: is not called however), the CLLocationManager delegate is setup and it’s didEnterRegion delegate method is called.
In my case, this sets up a UILocalNotification which is presented immediately (banner displays on home screen if for example another app is in use, or on the lock screen if phone is dormant).
The user actions the notification by swiping in the lock screen or tapping the banner, the app is launched and appWillEnterForeground/appWillBecomeActive is called AND the app delegate didRecieveLocalNotification: method is called if implemented.
This is my understanding, which is probably wrong as my UILocalNotification is never fired if the app is in the background. Could someone clarify which bits are wrong?
After further testing I've come to the conclusion that there's nothing wrong with my code and it's actually appears to be Apples implementation of region monitoring being poor. It seems to be only slightly better than the monitoring of significant location changes, and still relies on changes in wifi networks and cell towers. Even within a major UK city I found didEnterRegion wasn't trigged until you were up to 1000 meters into a mile wide region, if triggered at all. This explains why it works every time when testing though Xcode and forcing the location.
The only work around I've come up with so far is to calculate the distance remaining each time the users location is updated and to manually call the didEnterRegion delegate method when this is less than the regions radius/2. This is supposed to be done automatically by Apples code when you're more than 10m into the boundary, however I found that to be unreliable for the reasons above.
However given you can't get regular updates using the better accuracy of GPS whilst the app is in the background and this is only a problem when the app is in the background, it's not really a solution at all. :o(
Even though I called stopUpdatingLocation on my location manager, the location manager icon is still on the top right of my iPhone. Why hasn't it stopped?
There are several reasons why the location arrow on your phone may still be on even after calling stopUpdatingLocation.
For one, another app on your phone may currently be using your location.
Another possibility is that you enabled significant location change monitoring using the startMonitoringSignificantLocationChanges method but forgot to turn this off using the stopMonitoringSignificantLocationChanges method. Apps that are monitoring significant location changes will display a solid arrow in the status bar in the same way apps that are using standard location updates do.
Of course it's also possible that you are for whatever reason incorrectly calling stopUpdatingLocation and you actually are still getting location updates from a location manager. To check if this is happening wait several minutes after calling stopUpdatingLocation and go to Settings>Privacy>Location Services and find your app. If there is a solid purple arrow next to your app then your app is indeed currently using location services and something most likely went wrong when calling stopUpdatingLocation. However if there is a solid gray arrow, this just signifies that your app has recently used location services and it's likely that you did correctly stop getting updates. Another way to check if you correctly turned off location updates is by calling your CLLocationManager's location property and checking its timestamp property to make sure that it is not recent. If the timestamp is greater than the timestamp at which you called stopUpdatingLocation then you know something is wrong.
The icon you see at the top is not locationManager, is the location service of the device. If you deactivate in settings no longer appears.
I have a problem with my App based in Region Monitoring in iOS;
Suppose that I have a Monitored Region with 300 meters radius, and my location is 350 meters off the center of that region (but I am into a car moving get closer to my region).
If I close my App in that moment the GPS is turned Off instantly and the method "didEnterRegion" is never called. This problem doesn't happen if my location is farther to my region monitored (for example 500 meters away)
Is possible to fix this? I tried with "Background modes" setting the "Required location services" in background, but this make to use the GPS instead "Region Monitoring" and the GPS never stops.
The problem with Region Monitoring is that this function never works when the user is already "inside the region", then this causes a lot of problems for the in time notification.
First, you don't need background mode for region monitoring to work, region monitoring will continue to function even if you Sleep your device(pressing the top button). Plus Apple can reject your app if you don't use BG mode according to how they need it.
For your issue, if you are already inside and you are not getting a didEnterRegion for whatever reasons, you should use a backup plan. In your CLRegion class you can call containsCoordinate to see if you are inside the region.
You did not get a didEnterRegion call probably for some reason your add region gets reinitialized. I.e. you have re-added your region.
Dear fellow developers,
I am trying hard to find a solution for my problem regarfing CLLocationManager.
I use a CLLocationManager instance in my Application. If the user selects the Home button on the device or terminates the application I want the location services to stop.
Therefor I call [self.locationManager stopUpdatingLocation]; - But this somehow doesn't work. The application enters the background and the small location arrow in the upper right corner of the status bar don't disappear. Even if I add [self.locationManager release] or self.locationManager.delegate = nil; - the location tracking don't stop :-/
It only disappears if I go to my device settings and switch off location services for the app. Whenever I switch back to location service enabled I immediately get a purple colored arrow next to the switch toggle and the icon reappears in the status bar.
My question is how can I turn off location services when the app enters the background or is terminated?
Thanks a lot in advance and have a nice day :-)
Your location is disabled. The location service icon "meaning" has changed on iOS 5. Take a look at this question: https://apple.stackexchange.com/questions/27463/why-is-the-location-services-icon-always-present
I Quote the answer:
It's a new feature in ios 5 called "region Monitoring"
The reason it's active even if the app is closed is that this feature
runs in iOS 5 core and notifies all apps that are registered when they
have entered or left a specific geo-fence.
Reminders does that when you use a location based reminder.
Although the location icon appears at all time. This actually has very
minimal impact on the battery due to apple really optimizing this
feature by using cell and wifi mostly.
Your app is working ok. The system behaviour is the one who changed.
You do it the right way. When entering background, it's ok if some delegate methods are called for some seconds. That should stop.
Where do you stop the location updates ? Are you sure it is triggered ? If yes, are your delegate method called even if the visual indicators tell something else ?
Are you sure you don't trigger a method that reactivate the location update after you have stopped it (because for example you can receive some updates even after stopped).
For instance if you started monitoring a significant location change, then you should unsubscribe from it with the corresponding pair method. If you are using region enter, then until you unsubscribe, the system will notify your delegates.